JP2000130704A - Deaerator controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably control the water level in a deaerator when a plant load abruptly changes, by adding the flow rates of heating steam and the drain of a high-pressure feed water heater to the flow rate of the condensate flowing in the deaerator at the inlet of the deaerator, and adding the flow rate of circulated low-pressure cleaning-up water to the flow rate of the water flowing in the deaerator. SOLUTION: The flow rate value of heating steam which flows in a deaerator 12 is measured by means of a heating steam flow rate detector 91 and its transmitter 92, and the flow rate value of the drain of a high-pressure feed water heater is measured by means of a drain flow rate detector 93 and its transmitter 94. The flow rate of the water flowing in the deaerator 12 is decided by adding the measured values to the measured value of the condensate flowing in the deaerator 12 measured by means of an inlet condensate flow rate detector 72 and its transmitter 73. On the other hand, the flow rate of the water flowing out of the deaerator 12 is decided by adding the measured value of circulated low-pressure cleaning-up water measured by means of a cleaning-up water flow rate detector 95 and its transmitter 96 to the measured value of a boiler inlet feed water flow rate detector 74 and its transmitter 75. Therefore, the accuracy of the flow rates of the flowing-out/in water of the deaerator 12 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator control device for controlling a water level of a deaerator of a steam turbine plant and enabling a stable continuous operation of a boiler water supply system.

[0002]

2. Description of the Related Art Generally, a deaerator for removing non-condensable gas such as dissolved oxygen and carbon dioxide gas in a condensate is installed in a condensate / supply line in a steam turbine plant, and a boiler and other auxiliary equipment are provided. Is not corroded. There are various types of deaerators, and typical ones are a twin-body type in which a deaerator (deaeration heating chamber) and a water storage tank are connected by a water supply communication pipe and an equalizing pipe, and There is a single-body type or the like in which a structure is integrated. Here, the case of a twin-body type will be described.

The main system of the steam turbine plant and the deaerator control device are configured as shown in FIG.
In FIG. 14, steam discharged from a steam turbine 1 is condensed in a condenser 2 to be condensed, and the condensate pump 3
The condensate is sent to a condensate booster pump 8 via a condensate preheater 5, a condensate desalination device 6, and a ground steam condenser 7 via a condensate pipe 4. The condensed water is further raised in pressure by the condensed water booster pump 8 and the first low-pressure feed water heater 9 and the second low-pressure water heater 9 are controlled while controlling the throttle flow by the condensed water flow detector 53 and the deaerator water level control valve 77. After passing through the feed water heater 10 and the third low-pressure feed water heater 11 and passing through the deaerator inlet condensate condensate flow rate detector 72 (some plants are not installed), a spray valve (not shown) above the deaerator 12 is provided. The condensate is sprayed and atomized.

The condensed water flow detected by the condensed water flow detector 53 is input from a condensed water flow oscillator 54 to a condensed water recirculation flow controller 55, and condensed water recirculated through a condensed water recirculation pipe 51. The flow control valve 52 is adjusted to control the condensate recirculation flow to control the condensate flow supplied to the deaerator 12.

The condensed water guided to the deaerator 12 undergoes heat exchange by direct contact with the heated steam introduced into the deaerator 12, and corresponds to the operating pressure of the deaerator 12, as described later. The saturation temperature. Diffusion and deaeration are performed by this rapid heat exchange, and most of the deaeration during condensing is achieved. The non-condensed gas released from the condensate
2 is continuously released to the atmosphere from the top.

[0006] The deaerator 12 serves both deaeration and heating so that there is an alias of a deaeration heater. In a start-up / low-load castle, a deaerator is used as one of plant start-up steam from an auxiliary boiler (not shown). The auxiliary steam 31 is supplied to the deaerator 12 through the small deaerator pressure control valve 83 and the large deaerator pressure control valve 84. When the load exceeds a certain load (generally, a 25% load), the bleeding from the steam turbine 1 is started, and the deaerator 12 including the feed water heaters 9, 10 and 11 is started.
The turbine bleed air 32 is also supplied.

As the bleeding starts and the load of the steam turbine 1 increases, the bleeding pressure also increases, and the deaerator pressure control valve large valve 84 and the deaerator pressure control valve small valve 83
Is fully closed. On the other hand, when the load decreases,
Based on the pressure of the deaerator 12 from the deaerator pressure transmitter 82, the deaerator pressure regulator 82 controls the deaerator pressure regulator large valve 8
A control signal is transmitted to both the valve 4 and the deaerator pressure regulating valve small valve 83 to control both valves in the opening direction to supply steam to the deaerator 12 continuously.

[0008] The deaerator pressure control valve is a small valve 83 and a large valve 8
There are 4 and 2 valves because the deaerator 12
This is to prevent air from being mixed into the air. That is,
In order to maintain the pressure of the deaerator 12 at a small pressure by the small valve 83 and to supply a large amount of steam for heating vacuum deaeration by the large valve 84 with the aim of early startup in the plant startup preparation stage. It is. Also, it is for properly supplying the auxiliary steam until the start of the turbine bleeding after the start of the plant. That is, this is due to the inherent rangeability (controllability) of the control valve due to the large difference in the amount of steam required in the deaerator 12. One valve may be used as long as this characteristic is satisfied and controllable with one valve.

The water storage tank 13 stores the condensed water deaerated by the deaerator 12, and the deaerator 12 and the water storage tank 13.
Between the water supply connection pipe 14 for lowering the deaerated water, the pressure in the water storage tank 13 and the deaerator 12 when the load of the plant changes.
An equalizing pipe 15 for equilibrating with the internal pressure is provided. From the lower part of the water storage tank 13, the condensing system is flushed when the plant is started, and a low-pressure cleanup pipe 16 for cleaning the line is taken out. Water bowl 2
It is connected to the.

From the lower part of the water storage tank 13, a downcomer 21 which is a main system of the plant is further taken out, and the name of water is changed to water supply, and the boiler water supply booster pump 2 is changed.
2 has been contacted. The pressure of the pump 22 is further increased by a boiler feed pump (BFP) 24 via a feed pipe 23 to a first high-pressure feed water heater 25, a second high-pressure feed water heater 26, and a third high-pressure feed water heater 27. After that, it is supplied to the boiler 28.

At the outlet side of the boiler feed pump 24, a BFP recirculation pipe 61 for flowing feed water to prevent overheating of the poirer feed pump 24 at low load and low flow rate is branched.
The water supply is returned to the deaerator 12 via the FP overheat prevention valve 62, and the minimum flow rate passing through the boiler water supply pump 24 is secured. This flow control is performed by controlling the opening and closing of the BFP overheat prevention valve 62 by the BFP flow detector 63, the BFP flow transmitter 64 and the BFP overheat prevention flow controller 65 on the suction side of the boiler feed pump 24.

Further, each high pressure feed water heater 25, 26, 27
Is supplied with bleed air from the steam turbine 1 by a bleed pipe (not shown) to perform heat exchange by condensing water and indirect contact with the feedwater, and to send the drained one to the lower feedwater heater in order to further heat Exchange is taking place.

Here, the drain of the third high pressure feed water heater 27 is sent to the second high pressure feed water heater 26, and the drain of the second high pressure feed water heater 26 is sent to the first high pressure feed water heater 25. Have been. Depending on the plant's efficient thermal balance scheme, the third high pressure feedwater heater 27, below a certain load,
In some plants, the drain is collected from the second high-pressure feed water heater 26 directly to the deaerator 12 via a water level control valve (not shown) and used as feed water.

The drain of the first high-pressure feed water heater 25 is collected in a boiler blow tank via an external blow valve (not shown) until the water quality becomes stable (normal) when the plant is started. After the water quality is stabilized, the water level of the first high pressure feed water heater 25 provided in the heater drain pipe 45 of the first high pressure feed water heater 25 is controlled by the water level controller 48 of the first high pressure feed water heater 25. Control is performed by adjusting a valve (leading deaerator) 47 and a water level control valve (leading condenser) 46.

That is, until the load capable of sending the drain to the deaerator 12 is reached, the water level control valve (the deaerator) 47 of the first high-pressure feed water heater 25 is kept in a fully open state and waits. The water level is controlled by a water level control valve (leading condenser) 46 of the first high-pressure feed water heater 25. A so-called split range control method is adopted. Deaerator 1
The load that can send the drain to 2 is a load that allows the drain to be sent. As described above, the internal pressure of the first high-pressure feedwater heater 25 and the deaerator 12 is a pressure close to the extraction pressure from the steam turbine 1, and is proportional to the load. It is a load that enables the drain to be discharged in consideration of the pressure difference, the installation position difference between the second high-pressure feed water heater 26 and the deaerator 12, the pressure loss in the piping, the pressure loss in the water level control valve, and the like. .

Further, depending on the thermal equilibrium plan of the plant,
Also, a system for sending the water to the third low-pressure feedwater heater 11 via a water level control valve (not shown) may be provided. On the other hand, the drain of the low-pressure feedwater heater system is sequentially sent to the third low-pressure feedwater heater 11, the second low-pressure feedwater heater 10, and the first low-pressure feedwater heater 9, and the first low-pressure feedwater heating is performed. Table 9
Is sent to a low pressure feed water heater drain tank (low pressure heater drain tank) 35 with a positional difference (head difference).

The drain of the low-pressure heater drain tank 35 is supplied to the low-pressure heater drain pipe 36 until the load at which the water quality is stabilized.
Then, the water is sent to the condenser 2 from a water level control valve (leading condenser) 40 of the low pressure heater drain tank 35. After the water quality is stabilized, the low-pressure heater drain pump 37 is started and the water level control valve (the condensing line) 4 of the low-pressure heater drain tank 35 is activated.
1 through a first low pressure feed water heater 9 and a second low pressure feed water heater 10 to a condensing pipe.

To the low-pressure heater drain tank 35, in addition to the drain from the first low-pressure feed water heater 9, the steam-type air preheater drain 38 and the steam converter drain 39 from the boiler system are also sent. It has become.

Next, the deaerator water level control will be described.
Among the control methods conventionally used for keeping the water level of the deaerator 12 constant, the most advanced one is the deaerator 12.
This is a so-called three-element control that detects changes in the water level, inflow condensate flow rate, and outflow feedwater flow rate, and adjusts the inflow condensate flow rate to keep the deaerator water level constant.

The water level of the deaerator 12 is detected by a deaerator water level transmitter 71 installed in the water storage tank 13, and the inflow condensate flow rate is determined by the deaeration installed at the outlet side of the third low-pressure feed water heater 11. The outlet water supply flow detector 72 and the deaerator inlet water condensate flow transmitter 73 perform the outflow feedwater flow, and the outlet water supply flow detector 74 installed at the outlet side of the third high pressure feedwater heater 27. And it is performed by the boiler inlet feed water flow transmitter 75. The detected water level of the deaerator 12, the inflow condensate flow rate, and the outflow feedwater flow rate are respectively input to the deaerator water level controller 76. After performing various arithmetic processing, the deaerator water level is used as a control signal. The water is sent to the control valve 77, and its opening is adjusted to adjust the water level of the deaerator 12. As a result, much more stable control can be provided as compared with the one-element control method in which only the deviation of the water level is detected to control the inflow condensate flow rate.

[0021]

However, even in the deaerator water level control device of the three-element control method, hunting of the deaerator water level may occur depending on the method of continuous use of the plant, and the deaerator water level is abnormal. When high, steam turbine 1
There is a case where the steam turbine 1 is damaged by generating backflow of the stored water into the steam turbine, so-called water induction. Also, if the deaerator water level is abnormally lowered, the boiler feed pump 2
In some cases, the net suction head of No. 4 may be insufficient, causing cavitation and damaging the boiler feed pump.

Further, when the pressure in the deaerator 12 and the water storage tank 13 is suddenly reduced, the stored water is flushed (re-evaporated) to be in a gas-liquid multi-phase state, and air bubbles are sucked into the boiler feed pump 24 so that a net suction head is formed. And the cavitation may occur due to the shortage, and the boiler feed pump 24 may trip, that is, stop the plant. Factors that may cause unstable water level control and trip of the boiler feed pump depending on the plan and operation of the plant are as follows.

First, there is a case related to water level control, in which the water level control becomes unstable due to the difference between the planned value of the balance of the flow rate of water flowing in and out of the deaerator 12 and the actual machine.

This is because, in addition to the condensate inlet condensate flow rate, the deaerator heating steam and each high-pressure feed water heater drain are added as the inflow flow rate, the deaerator water level is set to the plus side, and the boiler inlet feed water flow rate is added. This is because, when the plant is started, the flow rate returned to the condenser via the low-pressure clean-up control valve makes the water level of the deaerator negative.

Next, when the pressure inside the deaerator suddenly drops, the stored water is flushed due to a delay in following the stored water temperature of the water storage tank 13, thereby hindering the stable operation of the boiler water supply pump 24 and preventing the water level of the water storage tank 13 from being lost. This is the case where control is adversely affected.

Recently, it has been assumed that an efficient operation method corresponding to the power consumption, for example, DSS operation (daily start stop), the load change rate is increased by improving the load following performance, and a case where an accident occurs in the power transmission system. FCB
Early power transmission to the power transmission system after accident recovery by (Fast-Cut-Back) operation has also been desired as a regular application method.

The deaerator 12 is supplied with auxiliary steam or bleed air from the steam turbine 1 to perform a function of heating and deaeration. Since the water stored in the water storage tank 13 is at the saturation temperature of the internal pressure of the vessel at that time, during FCB operation, the load on the steam turbine 1 suddenly decreases, that is, the deaeration pressure is reduced or cut off, so that the deaerator is assisted. Switch to steam supply in steam pressure control system.

In this case, the stored water temperature does not immediately decrease in response to a rapid decrease in the internal pressure of the deaerator 12 or the water storage tank 13, so that the water stored in the water storage tank 13 is flushed and the water level detection and water level control system is controlled. Not only has a negative effect,
The water mixed in the air / water state falls below the net suction head, which is indispensable for stable operation of the boiler water supply booster pump 22 and the boiler water supply pump 24, and in some cases, is sucked into each pump with the air / water mixture to generate cavitation. Sometimes. In such a case, it becomes impossible to continue the operation of the pump, and there has been an inconvenience of stopping the flow rate of water supply, that is, stopping the boiler and the power plant.

It is an object of the present invention to provide a deaerator control device in which stable operation of a boiler feed pump is continued and reliability of water level control of a deaerator storage tank is improved.

[0030]

According to a first aspect of the present invention, there is provided a deaerator control apparatus comprising: a water level of a water storage tank of a deaerator; a flow rate of condensed water flowing into the deaerator; and an outflow from the deaerator. A deaerator control device that detects a change with the supply water flow rate, adjusts the inflow condensate flow rate, and controls the water level of the water storage tank by a three-element water level control that keeps the water level of the water storage tank constant.
The inflow condensate flow rate uses the deaerator inlet condensate flow rate plus the deaerator heating steam flow rate and the high pressure feedwater heater drain flow rate, and the outflow feedwater flow rate is the low pressure cleanup circulation to the boiler inlet feedwater flow rate. It is characterized in that a flow rate obtained by adding the flow rate is used.

In the deaerator control apparatus according to the first aspect of the present invention, the inflow condensate flow rate to the deaerator is determined by the deaerator inlet condensate flow rate and the deaerator heating steam flow rate and the high pressure feed water heater drain flow rate. Is used, and the outflow water supply flow from the deaerator is the boiler inlet water supply flow plus the low pressure clean-up circulation flow. This balances the flow rate of water flowing into and out of the deaerator.

The deaerator control apparatus according to the second aspect of the present invention is the deaerator control apparatus according to the first aspect, wherein the deaerator heating steam flow rate, the high-pressure feed water heater drain flow rate, and the low-pressure cleanup circulation flow rate are controlled by respective control valves. When the flow rate passing through is Q, the capacity coefficient of the control valve is Cv, the differential pressure across the control valve is ΔP, and the specific gravity of the fluid is G, Q = (Cv / 1.17) · √ (ΔP / G). It is characterized by using a flow rate.

In the deaerator control apparatus according to the second aspect of the present invention, in addition to the operation of the first aspect, the deaerator heating steam flow rate, the high pressure feed water heater drain flow rate, and the low pressure cleanup circulation flow rate are set to predetermined values. Use the value obtained from the formula. Thereby, installation of a measuring instrument can be suppressed.

According to a third aspect of the present invention, in the deaerator control apparatus according to the second aspect, the differential pressure across the control valve is a detection signal of a differential pressure transmitter that detects the differential pressure across the control valve. Alternatively, a difference between detection signals from two pressure transmitters provided before and after the control valve is used.

In the deaerator control apparatus according to the third aspect of the present invention, in addition to the function of the second aspect of the present invention, the differential pressure before and after the control valve used in the predetermined formula is detected by a differential pressure transmitter. Alternatively, a difference between detection signals detected by two pressure transmitters provided before and after the control valve is used.

According to a fourth aspect of the present invention, in the deaerator control apparatus according to the second aspect, the specific gravity of the fluid uses a specific gravity calculated based on a fluid temperature upstream of the control valve. It is characterized by the following.

In the deaerator control apparatus according to the fourth aspect of the present invention, in addition to the operation of the second aspect, the specific gravity of the fluid used in the predetermined computer is determined based on the fluid temperature at the upstream side of the control valve. calculate.

According to a fifth aspect of the present invention, in the deaerator control apparatus according to the second aspect of the present invention, the specific gravity of the fluid is based on a fluid temperature based on a heat balance diagram of the plant for each load of the steam turbine which is planned in advance. Using the calculated specific gravity, the differential pressure before and after the control valve is characterized by using a differential pressure that takes into account the pipe pressure loss and the head difference between the upstream and downstream processes.

In the deaerator control apparatus according to the fifth aspect of the present invention, in addition to the operation of the second aspect of the invention, the specific gravity of the fluid used in the predetermined calculation formula is determined in advance by the plant planned for each load of the steam turbine. Is calculated based on the fluid temperature according to the thermal equilibrium diagram of FIG. As the pressure difference before and after the control valve, a pressure difference taking into account the pipe pressure loss and the head difference between the upstream and downstream processes is used.

According to a sixth aspect of the present invention, in the deaerator control apparatus according to the second aspect of the present invention, the capacity coefficient of the control valve is a capacity determined based on a detection signal of an opening degree transmitter of the control valve. It is characterized in that coefficients are used.

In the deaerator control apparatus according to the sixth aspect of the present invention, in addition to the operation of the second aspect of the present invention, the capacity coefficient of the control valve used in the predetermined formula is determined by the detection of the control valve opening transmitter. Determined based on the signal.

The deaerator control apparatus according to the seventh aspect of the present invention is the deaerator control apparatus according to the first aspect, wherein the deaerator heating steam flow rate, the high pressure feed water heater drain flow rate, and the low pressure cleanup circulating flow rate are set in respective piping lines. It is characterized by using the measured values by the attached flow detector and flow transmitter.

In the deaerator control apparatus according to the seventh aspect of the present invention, in addition to the operation of the first aspect, the deaerator heating steam flow rate, the high pressure feed water heater drain flow rate, and the low pressure cleanup circulation flow rate are respectively Detect with a flow detector and a flow transmitter attached to the piping line.

The deaerator control apparatus according to an eighth aspect of the present invention is the deaerator control apparatus according to the first aspect, wherein the condensate recirculation is performed based on the condensate booster pump outlet condensate flow rate instead of the deaerator inlet condensate flow rate. The flow rate is subtracted, and the condensate flow rate obtained by adding the flow rate of the low pressure heater drain from the low pressure heater drain tank is used.

In the deaerator control apparatus according to the eighth aspect of the present invention, instead of the operation of the first aspect of the present invention, the inflow condensate flow rate is
The condensate booster pump outlet condensate condensate recirculation flow is subtracted from the condensate recirculation flow, and the low-pressure heater drain flow from the low-pressure heater drain tank is added to the condensate flow. The flow rate is obtained by adding the flow rate.

According to a ninth aspect of the present invention, in the degassing control apparatus according to the eighth aspect, the condensate recirculation flow rate and the low-pressure heater drain flow rate are determined by setting a flow rate passing through each control valve to Q, Where Cv is the capacity coefficient, ΔP is the differential pressure across the control valve, and G is the specific gravity of the fluid, Q = (Cv / 1.
17) It is characterized by using the flow rate determined by √ (ΔP / G).

In the deaerator control apparatus according to the ninth aspect of the present invention, in addition to the operation of the eighth aspect, the condensate recirculation flow rate and the low-pressure heater drain flow rate are determined by the predetermined formulas of the second aspect. Use

According to a tenth aspect of the present invention, in the deaerator control apparatus according to the ninth aspect, the differential pressure across the control valve is a detection signal of a differential pressure transmitter that detects the differential pressure across the control valve. Alternatively, a difference between detection signals from two pressure transmitters provided before and after the control valve is used.

In the deaerator control apparatus according to the tenth aspect of the present invention, in addition to the function of the ninth aspect, the differential pressure before and after the control valve used in the predetermined formula is detected by a differential pressure transmitter. ,
Alternatively, a difference between detection signals detected by two pressure transmitters provided before and after the control valve is used.

In the deaerator control apparatus according to an eleventh aspect of the present invention, in the ninth aspect of the present invention, the specific gravity of the fluid uses a specific gravity calculated based on a fluid temperature upstream of the control valve. It is characterized by the following.

In the deaerator control apparatus according to the eleventh aspect, in addition to the effect of the ninth aspect, the specific gravity of the fluid used in the predetermined computer is based on the fluid temperature upstream of the control valve. calculate.

According to a twelfth aspect of the present invention, in the degassing control device according to the ninth aspect, the specific gravity of the fluid is determined based on a fluid temperature according to a thermal equilibrium diagram of the plant for each load of the steam turbine planned in advance. Using the calculated specific gravity, the differential pressure before and after the control valve is characterized by using a differential pressure that takes into account the pipe pressure loss and the head difference between the upstream and downstream processes.

In the deaerator control apparatus according to the twelfth aspect of the present invention, in addition to the function of the ninth aspect, the specific gravity of the fluid used in the predetermined calculation formula is determined in advance by the plant for each load of the steam turbine planned in advance. Is calculated based on the fluid temperature according to the thermal equilibrium diagram of FIG. As the pressure difference before and after the control valve, a pressure difference taking into account the pipe pressure loss and the head difference between the upstream and downstream processes is used.

According to a thirteenth aspect of the present invention, in the degassing control device according to the ninth aspect, the capacity coefficient of the control valve is a capacity determined based on a detection signal of an opening degree transmitter of the control valve. It is characterized in that coefficients are used.

In the deaerator control apparatus according to the thirteenth aspect, in addition to the function of the ninth aspect, the capacity coefficient of the control valve used in the predetermined formula is determined by detecting the opening degree of the control valve. Determined based on the signal.

According to a fourteenth aspect of the present invention, in the degassing control device according to the eighth aspect, the condensate recirculation flow rate and the low-pressure heater drain flow rate are determined by using a flow rate detector and a flow rate detector attached to each piping line. It is characterized by using a measurement value by a transmitter.

According to the deaerator control apparatus of the fourteenth aspect, in addition to the operation of the eighth aspect, the condensate recirculation flow rate,
The flow rate of the low-pressure heater drain is detected by a flow rate detector and a flow rate transmitter attached to each piping line.

According to a fifteenth aspect of the present invention, there is provided a deaerator control device for controlling a change in a water level of a water storage tank of a deaerator, a flow rate of a condensed water flowing into the deaerator, and a flow rate of a feedwater flowed out from the deaerator. In the deaerator control device for detecting and controlling the inflow condensate flow rate and controlling the water level of the water storage tank by three-element water level control for keeping the water level of the water storage tank constant, auxiliary steam is supplied to the deaerator. In this case, the set value of the deaerator pressure controller for adjusting the pressure control valve so that the pressure in the deaerator becomes a predetermined set value is extracted from the steam turbine by the bleeding supply from the steam turbine is started. Thereafter, the pressure is changed to follow the pressure at a value slightly lower than the internal pressure of the deaerator or the extraction pressure from the steam turbine.

In the deaerator control apparatus according to the fifteenth aspect, the set value of the deaerator pressure controller is such that when the bleeding supply from the steam turbine to the deaerator is started, the deaeration at that time is started. The follow-up change is performed at a value slightly lower than the pressure in the brass apparatus or the extraction pressure from the steam turbine.

According to a sixteenth aspect of the present invention, in the degasser control device according to the fifteenth aspect, the deaerator that follows and changes at a value slightly lower than the deaerator internal pressure or the bleed pressure from the steam turbine. The set value of the gas pressure controller is changed at a predetermined predetermined drop rate when the pressure in the deaerator, the extraction pressure from the steam turbine, or the load drop rate exceeds a predetermined value. It is characterized by doing so.

In the deaerator control apparatus according to the sixteenth aspect, in addition to the operation of the fifteenth aspect, the pressure in the deaerator, the pressure of the bleed air from the steam turbine, or the rate of decrease of the load becomes a predetermined value. If it exceeds, the set value of the deaerator pressure controller is changed at a predetermined drop rate.

According to a seventeenth aspect of the present invention, in the degasser control apparatus according to the sixteenth aspect, the set value of the deaerator pressure controller is a saturation value obtained based on the pressure in the deaerator. It is characterized in that the temperature has a pressure value higher than the water storage temperature of the water storage tank or the suction water supply temperature of the boiler water supply pump.

In the deaerator control apparatus according to the seventeenth aspect of the present invention, in addition to the operation of the sixteenth aspect, the deaerator pressure controller further comprises a saturation temperature obtained based on the pressure inside the deaerator. The pressure inside the deaerator is controlled so that the pressure value becomes higher than the water storage temperature of the water storage tank or the suction water temperature of the boiler water supply pump.

According to the eighteenth aspect of the present invention, in the degasser control apparatus according to the seventeenth aspect, the saturation temperature in the deaerator is obtained by subtracting a water head to a water storage tank from a suction pressure of a boiler feed pump. It is determined based on the determined pressure.

In the deaerator control apparatus according to the eighteenth aspect of the present invention, in addition to the operation of the seventeenth aspect, the saturation temperature in the deaerator is determined by the head pressure from the suction pressure of the boiler feed pump to the water storage tank. Is obtained based on the pressure obtained by subtracting.

A deaerator control apparatus according to a nineteenth aspect of the present invention provides a deaerator control device for controlling a change in a water level of a water storage tank of a deaerator, a flow rate of condensed water flowing into the deaerator, and a flow rate of a feedwater flowed out from the deaerator. In the deaerator control device for detecting and controlling the inflow condensate flow rate and controlling the water level of the water storage tank by a three-element water level control for keeping the water level of the water storage tank constant, at the start of the first cutback operation, It is characterized in that water having a temperature lower than the storage water temperature is injected into the tank or the deaerator, and the storage water corresponding to this is discharged.

In the deaerator control apparatus according to the nineteenth aspect, at the time of starting the first cutback operation, water having a temperature lower than the storage water temperature is injected into the water storage tank or the deaerator, and the water corresponding to this is stored. Let out.

According to a twentieth aspect of the present invention, in the degasifier control device according to the nineteenth aspect, the water injected into the water storage tank or the deaerator is supplied from a condensate booster pump or a condensate pump outlet line. It is a condensate to be taken out.

According to a twentieth aspect of the present invention, in addition to the function of the nineteenth aspect, the deaerator is provided with a condensate condensate taken out from a condensate booster pump or a condensate pump outlet line. Water to be injected into the inside.

According to a twenty-first aspect of the present invention, in the degasser control device according to the nineteenth or twentieth aspect, the water injected into the water storage tank or the deaerator is supplied from a low-pressure heater drain pump outlet line. It is a low-pressure heater drain to be taken out.

In the deaerator control apparatus according to the twenty-first aspect, in addition to the functions of the nineteenth and twentieth aspects, the low-pressure heater drain taken out from the low-pressure heater drain pump outlet line is supplied to a water storage tank or a deaerator. Water to be injected into the inside.

According to a twenty-second aspect of the present invention, in the deaerator control apparatus according to the twentieth or twenty-first aspect, the source of the water that flows out when the condensate water or the low-pressure heater drain is injected is the water storage source. It is characterized by a tank or downcomer, and the outflow to a condenser.

In the deaerator control apparatus according to the twenty-second aspect, in addition to the function of the twentieth or twenty-first aspect, when condensing water or injecting a low-pressure heater drain, water is stored from a water storage tank or a downcomer pipe. Remove and drain into condenser.

According to a twenty-third aspect of the present invention, in the degassing control device according to the twenty-second aspect, the water discharged when the condensate or the low-pressure heater drain is injected is supplied to a spillover control valve provided in a spillover pipe. And the low-pressure clean-up control valve provided in the low-pressure clean-up pipe is used in combination for the outflow.

According to the deaerator control apparatus of the twenty-third aspect, in addition to the function of the twenty-second aspect, a spillover control valve and a low-pressure clean provided in a spillover pipe when condensing or injecting a low-pressure heater drain are provided. The water is drained using the low pressure clean-up control valve provided in the up pipe.

According to a twenty-fourth aspect of the present invention, in the degasser control apparatus according to the twentieth or twenty-first aspect, the amount of water injected into the water storage tank or the deaerator is:
The injection flow rate control is performed based on a predetermined flow rate value in consideration of the replacement time of the storage water, and the outflow flow rate of the storage water is a follow-up flow rate control with a value slightly larger than the injection flow rate.

In the deaerator control apparatus according to the twenty-fourth aspect of the present invention, in addition to the operation of the twentieth or twenty-first aspect, the amount of water to be injected into the water storage tank or the deaerator is determined by the replacement time of the stored water. The flow rate of the stored water is controlled by the injection flow rate control based on the predetermined flow rate value considered, and the flow rate of the stored water is controlled by the follow-up flow rate control at a value slightly larger than the injection flow rate.

According to a twenty-fifth aspect of the present invention, in the degasifier control apparatus according to the twenty-second or twenty-third aspect, the amount of water injected into the water storage tank or the deaerator is:
As the following flow rate control at a value slightly smaller than the outflow flow rate of the stored water, the outflow flow rate is set to an outflow flow rate control based on a predetermined flow rate value.

In the deaerator control apparatus according to the twenty-fifth aspect, in addition to the operation of the twenty-second or twenty-third aspect, the amount of water to be injected into the water storage tank or the deaerator is:
The flow rate is controlled by the following flow rate control with a value slightly smaller than the flow rate of the stored water, and the flow rate is controlled by the flow rate control by a predetermined flow rate value.

According to a twenty-sixth aspect of the present invention, in the degasser control device according to the twenty-fourth or twenty-fifth aspect, the flow rate of the amount of water to be injected into the water storage tank or the deaerator and the amount of outflow of the stored water is determined. Each flow value to be fed back to the control is characterized by using a measured value by a flow detector and a flow transmitter attached to each piping line, or using the flow value obtained in claim 2.

According to a twenty-sixth aspect of the present invention, in addition to the functions of the twenty-fourth and twenty-fifth aspects, the deaerator control apparatus further includes a control unit that controls the amount of water injected into the water storage tank or the deaerator and the amount of outflow of the stored water. For each flow value to be fed back to the flow control, a value measured by a flow detector and a flow transmitter attached to each piping line is used. Claim 2
Use the flow rate value obtained in Step 2.

According to a twenty-seventh aspect of the present invention, in the degassing control device according to the nineteenth aspect, after the first cutback operation reaches the isolated operation load in the power plant and continues the stable operation, the stored water is dissolved. The deaerator circulation pump is started, operated, and stopped according to the relationship between the oxygen value or the storage water temperature and the saturation temperature of the internal pressure.

In the deaerator control apparatus according to the twenty-seventh aspect, in addition to the operation of the nineteenth aspect, the first cutback operation reaches the isolated operation load in the power plant and continues the stable operation. The deaerator circulation pump is started, operated, and stopped according to the relationship between the dissolved oxygen value or the storage water temperature and the saturation temperature of the internal pressure.

[0084]

Embodiments of the present invention will be described below. FIG. 1 is a system diagram of a steam turbine plant including a deaerator control device according to a first embodiment of the present invention.
The first embodiment is different from the conventional example shown in FIG. 14 in that the deaerator heating steam flow rate detector 91 and the deaerator heating steam flow rate detector 91 which detect and measure the deaerator heating steam flow rate and input to the deaerator water level controller 76. A vapor heating steam flow rate oscillator 92; a high pressure feed water heater drain flow rate detector 93 and a high pressure feed water heater drain flow rate oscillator 94 which measure and detect the high pressure feed water heater drain flow rate and input to the deaerator level controller 76; A low-pressure clean-up circulating flow rate detector 95 and a low-pressure clean-up circulating flow rate oscillator 96 which detect and measure the clean-up circulating flow rate and input to the deaerator water level controller 76 are additionally provided. The other configuration is the same as that of the conventional one shown in FIG. 14, and therefore, the same elements are denoted by the same reference numerals and overlapping description will be omitted.

In addition to the signal from the deaerator water level transmitter 71 for detecting the water level deviation in the three-element control method for the deaerator water level, the deaerator uses the change in the inflow and outflow of the deaerator 12 as a leading element. It is input to the water level controller 76 and the inflow condensate flow rate is adjusted by the deaerator water level control valve 77 to keep the water level in the water storage tank 13 constant.

The deaerator heating steam flow rate value as the inflow-side flow rate is obtained by measuring a deaerator heating steam flow rate detector 91 and a deaerator heating steam flow rate transmitter 92, and the high pressure feed water heater drain flow rate value is obtained. Is a high pressure feed water heater drain flow detector 9
3 and high pressure feed water heater drain flow transmitter 94 provide measurements. These are supplied to the deaerator inlet condensate flow detector 7
In addition to the measured value obtained by the deaerator inlet / outlet condensate flow transmitter 73, the flow rate into the deaerator 12 is used.

On the other hand, the low-pressure clean-up flow rate value as the outflow-side flow rate can be measured by the low-pressure clean-up flow rate detector 95 and the low-pressure clean-up flow rate transmitter 96, and the measured value is obtained by the boiler inlet feed water flow rate flow rate detector 74 and The outflow flow rate from the deaerator 12 is used in addition to the value measured by the boiler inlet supply flow rate transmitter 75. Thereby, the deaerator 1
The accuracy of the outflow / inflow rate of the second water is increased, and a correct change in the outflow / inflow rate as a preceding control element can be grasped.

In FIG. 1, the flow of the drain of the high pressure feed water heater to the deaerator 12 is described only from the first high pressure feed water heater 25. However, the second high pressure feed water is supplied according to the heat balance plan of the plant. It goes without saying that a plant having a system that flows from the heater 26 and the third high-pressure feed water heater 27 to the deaerator 12 is also added as the inflow flow rate. In order to prevent the boiler feed pump 24 from overheating at the low flow rate castle, the flow rate circulating from the BFP recirculation pipe 61 to the deaerator 12 through the BFP overheat prevention valve 62 is determined by the deaerator 12
It is not necessary to consider because the inflow and outflow of the water are the same.

As described above, the water storage tank 13 of the deaerator 12
In the so-called three-element water level control using the water level of the water storage tank 13, the deaerator inlet condensate flow rate, and the boiler inlet feedwater flow rate, the deaerator inlet condensate flow rate is used as the inflow condensate flow rate. The heating steam flow rate and the high pressure feed water heater drain flow rate are added, and the value obtained by adding the low pressure cleanup circulation flow rate to the conventional boiler inlet feed water flow rate is used as the outflow feed water flow rate.

Here, at the time of 100% load of the power plant, the deaerator inlet condensate flow rate was set to 10 for the inflow flow side.
If it is 0%, the deaerator heating steam flow rate occupies about 5% and the high-pressure feed water heater drain flow rate occupies about 25%, and flows into the deaerator 12 out of the calculation. On the other hand, a large amount of water is circulated from the water storage tank 13 of the deaerator 12 to the condenser 2 via the low-pressure clean-up control valve 17 although the flow rate on the outflow side is only when the plant is started. This is several times the boiler inlet feedwater flow rate, and the leading element of the water level control in each operation state is unbalanced, which indicates the instability of the water level control.

Therefore, in the first embodiment, the deaerator heating steam flow rate, the high-pressure feed water heater drain flow rate and the low-pressure cleanup flow rate are added to the outflow / inflow flow rate value of the deaerator 12 to obtain a correct flow rate value. , The preceding control is performed.
Therefore, stable water level control of the deaerator 12 can be performed.

Next, the deaerator heating steam flow rate, the high-pressure feed water heater drain flow rate and the low-pressure clean-up flow rate are determined by the deaerator heating steam flow rate detector 91, the deaerator heating steam flow rate oscillator 92, the high pressure feed water heater drain The flow rate may be detected and measured by the flow rate detector 93, the high pressure feed water heater drain flow rate oscillator 94, the low pressure cleanup circulating flow rate detector 95, and the low pressure cleanup circulating flow rate oscillator 96, but may also be obtained by the following formula. It is.

Q = (Cv / 1.17) · √ (ΔP / G) (1) where Q is the flow rate passing through the control valve, Cv is the capacity coefficient of the control valve, ΔP is the differential pressure across the control valve, G is the specific gravity of the fluid.

The deaerator heating steam flow rate passes through the deaerator pressure control valve small valve 83 and the deaerator pressure control valve large valve 84, and the high-pressure feed water heater drain flow rate is equal to the high-pressure feed water level control valve. The low-pressure clean-up flow passes through the low-pressure clean-up control 17 and flows into and out of the deaerator 12. The flow rate Q passing through each control valve is obtained by using the above expression for calculating the capacity coefficient of these control valves.

The measured value of the process amount required by the equation (1), that is, the differential pressure ΔP before and after the control valve is a detected value, and the specific gravity G is obtained by calculation based on the temperature of the fluid. In addition, a control valve opening signal is obtained, a control valve capacity coefficient Cv is obtained from a table of the control valve-specific valve opening and a capacity coefficient,
The flow rate Q of the control valve is calculated. As a result, a correct flow rate value can be obtained, and stable water level control using three factors can be performed.

The differential pressure ΔP required before and after the control valve in the calculation formula (1) is directly measured by the differential pressure transmitter 102 before and after the control valve as shown in FIG. Alternatively, as shown in FIG. 3, the pressures before and after the control valve are detected by the pressure transmitters 103 and 104, respectively, and P1−P2 = △ P.

In order to obtain the differential pressure (△ P) before and after the control valve required by the equation (1), the differential pressure oscillator 102 for detecting the pressure before and after each control valve is provided, or Pressure detectors 103, 104 before and after each control valve, respectively.
To determine the true differential pressure. Thereby, a correct flow rate value can be obtained, and stable water level control can be performed.

Further, the specific gravity G of the fluid required in the equation (1) is obtained from the temperature of a generally used fluid. This involves installing a temperature detector in front of each control valve, or calculating the specific gravity of the passing fluid at the temperature measured in the process upstream of each control valve.

As described above, in order to obtain the specific gravity G of the fluid passing through the control valves, a temperature detector is provided in front of each control valve to measure the temperature, or a process upstream of each control valve is used. The specific gravity is calculated using the thermometer-side value of the above. Therefore, a correct flow rate value can be obtained, and stable water level control can be performed.

Also, the differential pressure △ P required in the equation (1)
When obtaining the specific gravity G or the specific gravity G, it is also possible to obtain the specific gravity G as follows, instead of the above-described method. That is, a capacity calculation statement of the control valve using the specific gravity G from the temperature of the fluid based on the heat balance diagram of the plant for each load of the steam turbine planned in advance, the pressure loss of the piping described in this document, and the upstream and downstream sides A differential pressure ΔP taking into account the head difference of the process is used. Then, the flow rate is compared with the load signal of the steam turbine, and the difference between the control valve opening degree and the actual opening degree in the calculation document is corrected to obtain an approximate flow rate.

Here, the numerical values between the loads in the thermal equilibrium diagram are as follows:
By using the value to be proportionally interpolated, it is possible to control a continuous value that is close to the actual state, and it can be said that the deaerator control device is the cheapest and simplified one. In this case, it is necessary to prepare a thermal equilibrium diagram assuming the state of every plant, thereby to prepare a calculation book of the capacity of the control valve and to register it in advance in the deaerator control device.

As described above, the capacity calculation document of the control valve using the specific gravity G based on the thermal equilibrium diagram of the plant for each load of the steam turbine planned in advance, and the pressure loss and the head difference of the piping described in this document Is compared with the load signal of the steam turbine, and the flow rate is corrected by the control valve opening to obtain an approximate flow rate value Q. This makes it possible to perform a stable and stable water level control of the inflow and outflow flow rates of the deaerator 12.

The opening degree of the control valve required to derive the capacity coefficient Cv of the control valve required in the formula (1) is directly detected by attaching an opening transmitter to the control valve. .
Alternatively, it is determined by a control signal from each controller to each control valve.

Here, the directly detected signal of the valve opening degree is more reliable, but not only the opening degree transmitter and its fittings are required, but also signal cable construction is required, and the cost and the like are increased. And expensive. On the other hand, the control signal from each controller to the control valve may be different from the actual opening due to the operation delay of the control valve, and this point must be taken into consideration.

As described above, the opening degree of the control valve required to obtain the capacity coefficient Cv of the control valve is determined by the opening signal from the opening signal of the control valve or the control signal from the controller to the control valve. Since it is determined by the signal, a correct flow rate value can be obtained, and stable water level control can be performed.

Next, the deaerator heating steam flow rate, the high-pressure feedwater heater drain flow rate and the low-pressure cleanup flow rate are measured by the deaerator heating steam flow rate detector 91, the deaerator heating steam flow rate oscillator 92, the high-pressure feedwater heater drainage. A description will be given of a case where the flow rate is obtained from measurement values detected and measured by the flow rate detector 93, the high pressure feed water heater drain flow rate oscillator 94, the low pressure cleanup circulating flow rate detector 95, and the low pressure cleanup circulating flow rate oscillator 96.

Here, specifically, for each flow piping line,
An example of the case where the flow rate is measured by the flow rate detector and the flow rate transmitter will be described using a process value of 100% load in a thermal equilibrium diagram of one blunt. In FIG. 1, the deaerator heating steam flow rate by the deaerator heating steam flow rate detector 91 and the deaerator heating steam flow rate transmitter 92 is auxiliary steam and turbine bleed, and the pressure P (P = 15 kgf / cm)
² (K), temperature T (T = 4000 ° C.), and a slight increase in pressure loss in the piping is acceptable, so that it is possible to measure the throttle flow rate with a highly versatile flow orifice.

By using this value, it is possible to measure the flow rate of the auxiliary steam and the turbine bleed air after the merger, and it is possible to control the flow of the turbine bleed air without a control valve, which is the best method.

Next, in FIG. 1, the drain flow rate of the high-pressure feed water heater by the high-pressure feed water heater drain flow detector 93 and the high-pressure feed water heater drain flow transmitter 94 is represented by a temperature T (T
= 300 ° C. to 230 ° C.), and measurement by the throttle is inappropriate because the fluid flashes.
Therefore, a vortex flowmeter or the like that utilizes a change in pressure caused by the generation of Karman vortices having an insert inside the pipe is suitable, and an ultrasonic flowmeter for non-wetted measurement is also suitable.
In the case of the ultrasonic flowmeter for non-wetted measurement, it is necessary to improve the heat-resistant temperature of the detector.

Finally, the low-pressure cleanup flow rate detector 9
5 and the low-pressure clean-up flow rate by the low-pressure clean-up flow transmitter 96, which is also a temperature T (T = 18).
Since the saturation temperature is about 0 ° C.), an actual measurement can be performed by the same measuring method as the drain flow rate of the high-pressure feed water heater.

As described above, when each flow rate value is obtained by the flow rate detector and the flow rate transmitter attached to each piping line, the flow rate value can be obtained in the simplest manner, and a correct balance between the outflow and inflow flow rates can be obtained. Therefore, stable water level control of the deaerator water storage tank can be performed.

Next, a second embodiment of the present invention will be described. FIG. 4 is a system diagram of a steam turbine plant including a deaerator control device according to a second embodiment of the present invention.
The second embodiment differs from the first embodiment shown in FIG. 1 in that a condensate recirculation flow rate detector 97 for detecting and measuring the condensate condensate flow rate at the outlet of the condensate booster pump 8 and a condensate recirculation. A flow oscillator 98 is provided, and a low-pressure heater drain flow detector 99 and a low-pressure heater drain flow oscillator 100 for detecting and measuring the low-pressure heater drain flow from the low-pressure heater drain tank 35 are provided. The condensate recirculation flow rate is subtracted from the outlet condensate flow rate, and the condensate flow rate obtained by adding the low pressure heater drain flow rate from the low pressure heater drain tank 35 is used. The other configuration is the same as that of the first embodiment shown in FIG. 1, and therefore, the same components are denoted by the same reference symbols and overlapping description will be omitted.

In an existing power plant, for example, a plant constructed about 25 years ago, it is general that the deaerator inlet condensate flow rate on the inflow flow rate side is not measured. The second embodiment is applied.

In FIG. 4, the flow rate is measured by a condensate flow rate detector 53 and a condensate flow rate transmitter 54 installed at the outlet side of the condensate booster pump 8, and the condensate recirculation pipe 51 branched from the line ahead. , The flow rate circulating from the condensate recirculation flow control valve 52 to the condenser 2 is subtracted. Further, in the previous line, the pressure is raised by the low pressure heater drain pump 37 and the low pressure heater drain tank water level control valve (the condensing line ) Add the flow rate of the low-pressure heater drain that joins the condensate line via 41. As a result, the flow rate matches the deaerator inlet condensate flow rate value in the first embodiment.

As described above, in the second embodiment, the present invention is applied to an existing plant in which the deaerator inlet condensate flow is not measured, and the condensate recirculation flow is subtracted from the condensate booster pump outlet condensate flow. Then, the flow rate of the low-pressure heater drain from the low-pressure heater drain tank is added to make the inflow condensate flow rate into the deaerator 12.

Next, the condensate recirculation flow rate and the low pressure heater drain flow rate are detected by the condensate recirculation flow rate detector 97, the condensate recirculation flow rate transmitter 98, the low pressure heater drain flow rate detector 99, and the low pressure heater drain flow rate transmitter 100. Although the measurement may be performed, the measurement may be performed using the above-described calculation formula (1).

In this case, as in the first embodiment, the differential pressure required before and after the control valve in the formula (1) is determined by the detection signal of the differential pressure transmitter for detecting the differential pressure before and after the control valve, Alternatively, a difference between detection signals from two pressure transmitters provided before and after the control valve is used. Further, the specific gravity of the fluid required in the calculation formula (1) uses the specific gravity calculated based on the fluid temperature on the upstream side of the control valve. Alternatively, a specific gravity calculated based on a fluid temperature based on a plant thermal equilibrium diagram for each load of the steam turbine planned in advance is used. The differential pressure before and after the control valve may be a differential pressure that takes into account the pipe pressure loss and the head difference between the upstream and downstream processes. As the capacity coefficient of the control valve, a capacity coefficient obtained based on a detection signal from the opening transmitter of the control valve is used.

Next, the condensed water recirculation flow rate and the low pressure heater drain flow rate are detected by the condensed water recirculation flow rate detector 97, the condensed water recirculation flow rate transmitter 98, the low pressure heater drain flow rate detector 99, and the low pressure heater drain flow rate transmitter 100. The case of obtaining from measured values will be described.

The condensed water recirculation flow rate by the condensed water recirculation flow rate detector 97 and the condensed water recirculation flow rate transmitter 98 is equal to the pressure P (P
= 45K), temperature T (T = 34 ° C), and a slight increase in pressure loss can be tolerated. Therefore, versatile flow orifice measurement of throttle flow and non-wetted liquid by ultrasonic flow meter for heat resistance. However, measurement at the upstream side of the condensate recirculation flow rate control valve 52 is indispensable (because there is a high possibility of cavitation at the secondary side of the control valve).

The low-pressure heater drain flow rate by the low-pressure heater drain flow rate detector 99 and the low-pressure heater drain flow rate transmitter 100 is determined by the low-pressure heater drain pump 37.
(P = 26K), since the temperature is raised to about T (T = 130 ° C) and merged with the condensate line, it is possible to measure the throttle flow rate by using a flow orifice, etc. Also, the non-wetted ultrasonic flow rate By improving the heat-resistant temperature of the detector, its utilization can be expected together with the condensate recirculation flow rate.

Next, a third embodiment of the present invention will be described. FIG. 5 is a characteristic diagram illustrating pressure control characteristics of the deaerator control device according to the third embodiment of the present invention. This third
In the embodiment, after the set value P0 of the deaerator pressure controller 82 for adjusting the pressure control valves 83 and 84 is changed to a value after the bleeding supply from the steam turbine 1 to the deaerator 12 is started,
The follow-up change is performed at a value slightly lower than the internal pressure of the deaerator 12 or the extraction pressure from the steam turbine 1.

The storage of the deaerator 12 (steam seal), vacuum deaeration, and heating deaeration, and a deaerator pressure transmitter 81 and a deaerator pressure controller 82 for each operation state are used to determine the deaerator pressure. The control valve small valve 83 and the deaerator pressure control valve large valve 84 are opened and closed to supply the deaerator auxiliary steam 31 to the deaerator 12 and control it to maintain a predetermined pressure value.

In this case, when the load on the plant is small, auxiliary steam is supplied to the deaerator 12. However, as the load on the plant rises, a bleed source valve (not shown) is opened and the deaerator 12 is Is supplied with the turbine bleed air 32. When the pressure in the deaerator becomes a pressure exceeding the set value of the deaerator pressure regulator 82 due to the supply of the turbine bleed air 32, the control is shifted from the auxiliary steam supply control to the turbine bleed supply control.

FIG. 5 shows the transition state of the deaerator pressure or the bleed pressure in the operation state of the plant. The set value of the deaerator pressure regulator 82 remains the set value of the auxiliary steam supply control. Rather than being fixed, the set value P0 is changed to a value slightly lower than the deaerator internal pressure during turbine bleed supply or the turbine bleed pressure. In addition, when the extraction pressure decreases when the steam turbine load drops, this difference is maintained and the set value follows the deaerator internal pressure or the turbine extraction pressure, and when the predetermined pressure is reached, the auxiliary steam supply control is performed smoothly. Switch to.

Thus, control can be performed immediately even when the pressure in the chamber of the deaerator 12 or the bleed pressure suddenly decreases. That is, it is possible to solve a control delay in a situation caused by a so-called reset windup in which the control signal largely deviates from the signal range and becomes saturated by the integral control operation of the pressure controller 82. Therefore, the stable operation of the boiler feed pump 24 in the flush of the stored water due to the delay in following the decrease in the stored water temperature of the water storage tank 13 due to the abnormally rapid decrease in the pressure in the deaerator may be impeded, or the water level may be transmitted to the water level control system. It is possible to prevent disturbance such as sudden change and pulsation of the differential pressure.

Further, the set value P0 of the deaerator pressure controller is:
When the pressure in the deaerator, the bleed pressure from the steam turbine 1, or the load drop rate exceeds a predetermined value, the controller stops following the deaerator pressure or the bleed pressure and shown in FIG. Is changed at a predetermined descent rate.

That is, a sudden load drop (rapid bleeding pressure drop) such that a flush of the stored water occurs due to a delay in following the drop in the stored water temperature of the water storage tank 13 due to a decrease in the pressure in the deaerator, and this phenomenon occurs. If the pressure in the deaerator, the bleed pressure, or the rate of decrease in the load on the steam turbine 1 exceeds a predetermined value during load interruption or FCB at a large value which can occur naturally, as shown in FIG. Is changed to a value higher than the value of the bleed pressure or the internal pressure at that time, and the process immediately shifts to the auxiliary steam supply control.

In this case, the predetermined value is a predetermined value in the sense of a descent rate at which no flash occurs or a small amount of flash converges in relation to the followability of the water temperature drop.

As described above, when the internal pressure, the bleed pressure or the load drop rate exceeds a predetermined value when the load of the steam turbine drops, the set value P0 of the pressure controller 82 is changed to the internal pressure or the bleed pressure at that time. After setting to a slightly higher value, and after switching to the auxiliary steam supply control, the set value is reduced to a value that is more gradual than this rate of decrease (a value that takes into account the ability to follow the decrease in the stored water temperature), and Pressure control to reach the pressure is performed. As a result, flushing of the water stored in the water storage tank 13 can be prevented, and stable operation of the boiler water supply pump 24 and water level control can be performed.

The set value of the deaerator pressure controller 82 is:
When the pressure drop rate of the deaerator internal pressure, the bleed pressure or the load of the steam turbine 1 exceeds a predetermined value, instead of dropping at a predetermined rate, a saturation obtained based on the deaerator internal pressure is obtained. The pressure value is such that the temperature is higher than the water storage temperature of the water storage tank 13 or the suction water supply temperature of the boiler water supply pump 24.
That is, the set value of the deaerator pressure regulator 82 at the time of a sudden load drop of the steam turbine 1 is changed to a higher value, and the control is immediately switched to the auxiliary steam supply control.

In FIG. 7, the saturation temperature (Tdeae.sat.) Obtained from the pressure signal of the deaerator pressure transmitter 81 is compared with the water storage temperature (Ttnk) obtained from the water storage tank temperature detector 101, and Tdeae.sat Set the pressure value such that. ≧ Ttnk. That is, the pressure value that maintains the pressure in the deaerator is set as the set value of the pressure controller so that the stored water does not flush or converges with a slight flush. As a result, the control is switched to the auxiliary steam supply control at an early stage.

As described above, the set value P0 of the pressure controller when the load of the steam turbine suddenly drops is calculated by comparing the saturation temperature of the pressure inside the deaerator and the storage water temperature, and calculating the pressure inside the deaerator. The saturation temperature becomes higher than the storage water temperature, or the pressure value that coincides with the deaerator pressure controller 82 is set as a set value. Set value is reached.

In this case, instead of the saturation temperature (Tdeae.sat.) Obtained from the pressure signal of the deaerator pressure transmitter 81, as shown in FIG. 8, the pressure value (Pbfp) from the BFP suction pressure transmitter 105 is used. The saturation temperature (Tbfp.sa) obtained from the pressure obtained by subtracting the value obtained by multiplying the water head (h) from the water tank level to the specific gravity obtained by the temperature from the water tank temperature detector 101
t.) can also be used. That is, by comparing the saturation temperature (Tbfp.sat.) With the stored water temperature (Ttnk) obtained from the stored water temperature detector 101, the pressure value that satisfies Tbfp.sat. ≧ Ttnk is determined by the deaerator pressure controller 82. Set value.

In FIG. 9, the saturation temperature (Tdeae.sat.) Obtained from the pressure value of the deaerator pressure controller 81 and BF
In comparison with the temperature signal (Tbfp) from the P suction temperature detector 106, a pressure value satisfying Tdeae.sat. ≧ Tbfp is set as a set value of the deaerator pressure controller 82.

As described above, the set value of the deaerator pressure regulator 82 when the load of the steam turbine 1 suddenly drops is obtained from the pressure obtained by subtracting the water head to the storage tank 13 from the suction pressure of the boiler feed pump 24. The value obtained from the saturation temperature and the storage water temperature, or the value obtained by comparing the saturation temperature obtained from the pressure in the deaerator and the suction feedwater temperature is set as the set value of the deaerator pressure controller 82. Then, the set value is lowered at a predetermined descent speed to reach a predetermined set value of the internal pressure. This prevents flushing of the water stored in the water storage tank 13 and the boiler water supply pump suction water supply.

Next, a fourth embodiment of the present invention will be described. FIG. 10 is a system diagram of a steam turbine plant including a deaerator control device according to a fourth embodiment of the present invention,
Some descriptions are omitted. In the fourth embodiment, at the start of the first cutback operation, water having a temperature lower than the storage water temperature is injected into the water storage tank 13 or the deaerator 12, and the water stored in the storage tank 13 or the deaerator 12 is discharged. It is. And the water storage tank 13 or the deaerator 1
The water injected into 2 is condensate taken out from the outlet line of condensate booster pump 8 or condensate pump 3.

Sudden load drop including FCB (first cutback) operation of the steam turbine 1, or when the steam turbine 1 trips, abrupt drop in the bleed pressure causes the inside pressure of the deaerator 12 to drop sharply. . A large amount of water may be flushed due to a delay in following the drop in the water temperature of the water storage tank 13 with respect to the descent speed. In order to prevent the flushing, the water storage tank 13 or the deaerator 12 is used.
Inject water at a temperature lower than the water storage temperature. Along with this, the water stored in the tank is discharged according to the amount of water injected. As a result, the temperature is reduced by the early replacement of the stored water, and even if the pressure inside the deaerator suddenly drops, a large amount of flush of the stored water can be prevented.

Here, the water storage tank 13 is generally considered to be appropriate as a low-temperature water injection destination.
2 may be injected. This can be naturally predicted to further accelerate the pressure drop in the chamber due to contact with the heated steam, but for this, the addition of a partition by a structure (not shown) inside the deaerator 12 or By changing the size and the like of the water supply connection pipe 14 and the pressure equalizing pipe 15 to the water storage tank 13, the same effect as injecting the water into the water storage tank 13 can be obtained.

In FIG. 10, when the pressure inside the deaerator suddenly drops, the supply source of the low-temperature water to be injected into the water storage tank 13 or the deaerator 12 is as follows. Condensate from pipe 111a,
Or the temperature reduction pipe 111 taken out from the outlet of the condensate pump 3
Use the condensate from b. As a result, the water storage temperature can be lowered early. A flow control valve (or electric valve) 112 is provided in the temperature lowering pipe 111a.

The specific temperature in this case will be described using a thermal equilibrium diagram of one example plant. Now, 100% load
The water storage temperature is 184 ° C /
158 ° C, condensate booster pump outlet condensate 34 ° C / 3
4 ° C, and condensing pump outlet condensing at 33 ° C / 33 ° C,
It turns out that the water is low enough to lower the temperature.

The condensate to be taken out may not be the outlet of the condensate booster pump 8, but may be the outlet line of the condensate booster pump 8, for example, the outlet of the first low-pressure feed water heater 9, the second low-pressure feed water heating The outlet of the vessel 10 or the outlet of the third low-pressure feedwater heater 11 may be used.

In this case, the outlet condensate of the first low-pressure feed water heater 9 is 89 ° C./75° C., the outlet condensate of the second low-pressure feed water heater 10 is 120 ° C./104° C., and the third low-pressure feed water The condensate at the outlet of the feed water heater 11 is 151 ° C./130° C., and the respective temperatures are sequentially increased. Therefore, since the flow rate to be injected differs depending on the take-out point, a smaller amount is more desirable because the pipe diameter, length and other equipment costs are taken into consideration, and the condensate with a little more oxygen is mixed with the stored water.

Next, a fifth embodiment of the present invention will be described. FIG. 11 is a system diagram of a steam turbine plant including a deaerator control device according to a fifth embodiment of the present invention,
Some descriptions are omitted. This fifth embodiment is different from the fourth embodiment shown in FIG. 10 in that instead of the outlet line of the condensate booster pump 8 or the condensate pump 3, the outlet line of the low-pressure heater drain pump 37 is used. The heater drain is taken out as condensate.

The outlet of the low-pressure heater drain pump 37 is replaced with the outlet line of the condensate booster pump 8 or the condensate pump 3, instead of the outlet line of the condensate booster pump 8 or the condensate pump 3. From the outlet line of the low-pressure heater drain pump 37, the temperature-reducing pipe 111
The low-pressure heater drain is supplied to the deaerator 12 or the water storage tank 13 through the line c. A flow control valve (or electric valve) 112 is provided in the temperature lowering pipe 111c.

Here, in addition to the low-pressure heater drain, FIG.
As shown in FIG. 0, the condensate at the outlet line of the condensate booster pump 8 or the condensate pump 3 may be injected. The temperature of the low-pressure heater drain is, for example, 10
0 ° and 50% load, 123 ° C./104
It is ° C and it is worthy of use.

Further, the temperature reduction tubes 111a and 111b in the fourth embodiment shown in FIG.
Temperature reduction pipe 111c according to the fifth embodiment shown in FIG.
A flow control valve (or an electric valve) 112 is installed in the middle of the process. The flow rate control valve (electrically operated valve) 112 adjusts a predetermined flow rate value in consideration of the replacement time of the stored water by injection flow rate control, which is a set value of a flow rate controller (not shown). Also,
The outflow of the stored water is set to follow flow control at a value slightly larger than the injection flow.

In this case, “outflow flow rate> inflow flow rate” is satisfied, and the shortage of the inflow flow rate depends on the deaerator water level control system to recover the water level. Thereby, it is possible to avoid an abnormal rise in the water level and interference between the control systems.

As described above, the amount of water injected into the water storage tank 13 or the deaerator 12 in the deaerator control device is determined by the predetermined flow rate value in consideration of the replacement time of the stored water, that is, the storage temperature of the storage water due to the drop in the internal pressure. The injection flow rate is controlled by a flow rate value that prevents the flushing of the stored water due to the delay in following the drop. Thus, the required flow rate can be ensured, and the required flow rate can be ensured by additionally providing the flow control valve (electrically operated valve) 112 as the control operation end.

At this time, the outflow amount of the stored water in the water storage tank 13 is set to follow-up control with a value slightly larger than the injection flow rate.
In addition to avoiding abnormal rise of the water level in the water storage tank 13, replenishment of the flow rate of the slight water level reduction depends on the water level control system of the water storage tank of the deaerator 12.

Next, a sixth embodiment of the present invention will be described. FIG. 12 is a system diagram of a steam turbine plant including a deaerator control device according to a sixth embodiment of the present invention,
Some descriptions are omitted. The fifth embodiment is different from the fourth embodiment shown in FIG. 10 or the fifth embodiment shown in FIG. 11 in that the condensate or the drainage of the low-pressure heater drain is discharged. originally,
The storage tank 13 or the downcomer 21 is used, and the outflow destination is the condenser 2. Note that in FIG.
Illustration of 1a, 111b and 111c is omitted.

In FIG. 12, when low-temperature water is injected into the water storage tank 13 or the deaerator 12, the source of the stored water to be discharged is the water storage tank 13 or the downcomer 21.
The outlet is connected as a condenser 2 by a spillover pipe 113, and the flow rate is adjusted by a spillover valve 114. This makes it possible to reuse water by circulating water in a large system of the power plant. In other words, the outflow destination of the injection water is collected in the system as the condenser 2,
Efficient water replacement can be performed without water loss.

Here, a spillover control valve 114 is provided in the middle of the spillover pipe 113 as an outflow side of the stored water at the time of injecting low-temperature water in order to lower the stored water temperature of the water storage tank 13 at an early stage. ing. Also,
For the purpose of reducing the passing flow rate and reducing the equipment cost of the spillover pipe 113 and the spillover control valve 114,
A low-pressure clean-up valve 17 and a deaerator blow valve (not shown) that is taken out of the water storage tank 13 may be used in combination.

Further, the spillover valve 114 is used not only for controlling the outflow flow rate for the early fall of the storage water temperature, but also for the abnormal rise of the water level at the time of unexpected turbulence of the deaerator water level control system. It goes without saying that by controlling, it can be used for preventing water induction to the steam turbine 1.

Next, the flow rate of the low-temperature water into the water storage tank 13 or the deaerator 12 is set to follow-up flow control at a value slightly smaller than the flow rate at the outflow, and the flow rate is set to the flow rate control at a predetermined flow value. . Thereby, the required flow rate is ensured. In addition, since the outflow amount of the stored water in the water storage tank 13 is controlled at a value slightly larger than the injection flow rate, an abnormal rise in the water level in the water storage tank 13 is avoided. Then, the replenishment of the flow rate corresponding to the lowered water level depends on the storage tank water level control system of the deaerator 12.

For each flow value to be fed back to the flow control of the inflow of low-temperature water and the outflow of stored water, a flow detector and a flow transmitter are attached to each pipe, and the measured values are used. Alternatively, a flow rate value calculated by the calculation formula (1) is used.

Next, a seventh embodiment of the present invention will be described. FIG. 13 is a system diagram of a steam turbine plant including the deaerator control device according to the seventh embodiment of the present invention,
Some descriptions are omitted. This seventh embodiment is different from the fourth embodiment shown in FIG. 10 in that water stored in a water storage tank 13 is supplied to a deaerator 12 via a deaerator circulation pipe 121 by a deaerator circulation pump 122. A check valve 123 for preventing the inflow of condensate from the condensate pipe 4 is provided on the outlet side of the deaerator circulation pump 122. That is, a system provided with a check valve 128 at the end of the deaerator circulation pipe 121 and the deaerator circulation pump 122 taken out from the water storage tank 13 is additionally provided and connected to the condensate pipe 4.

When the condensed water or the low-pressure heater drain is injected to suppress the occurrence of flushing of the stored water in the water storage tank 13 at the time of a sudden load drop of the plant, the start of the FCB operation, or the load interruption, etc., the plant is operated stably. After the continuation of the above, the deaerator circulation pump 122 is started and operated to circulate the water storage according to the measured value of the dissolved oxygen meter of the storage water (not shown), whereby the oxygen content contained in the water storage is removed at an early stage. In this case, it goes without saying that the same effect can be obtained by obtaining the dissolved oxygen value from the relationship between the saturated temperature value of the deaerator internal pressure and the actually measured storage water temperature value instead of the dissolved oxygen value. Further, even when this operation is started, the inflow / outflow flow values are the same, so that there is no hindrance to the water level control by the three elements in the deaerator control device.

[0158]

As described above, according to the present invention, stable water level control is performed even when the plant load changes abruptly, and the pressure inside the deaerator due to a decrease in the turbine bleed pressure when the load suddenly decreases. Even when the water temperature decreases, the ability to follow the change in the stored water temperature can be improved, and the stable continuous operation of the boiler feed pump or the like can be continued.

According to the first aspect of the present invention, the deaerator heating steam, the high-pressure feed water heater drain, and the low-pressure cleanup flow are respectively added to the inflow / outflow flow rate as a preceding control element of the storage tank water level control of the deaerator. As a result, a correct balance of the outflow and inflow flow rates can be obtained, and thus the water level of the storage tank of the deaerator can be controlled stably in any operation state of the plant.

In the second aspect, the required flow rate value can be obtained from the formula for calculating the capacity coefficient of the control valve in addition to the first aspect. Water level control of the storage tank becomes possible.

In the third, fourth, fifth and sixth aspects, since the respective numerical values required in the second aspect can be obtained, a correct or approximate flow rate can be obtained, and the water level of the storage tank of the deaerator can be stabilized. Control becomes possible.

According to the seventh aspect, it is possible to obtain the required flow rate value by actually measuring the flow rate value additionally required in the first aspect, so that the water level of the storage tank of the deaerator can be controlled stably in any operation state of the plant. It becomes possible.

According to the invention of claim 8, the condensate recirculation flow rate is subtracted from this value by using the condensate flow rate at the condensate booth coupon outlet instead of the deaerator inlet condensate flow rate of claim 1. Further, since an approximate value is obtained by adding the low pressure heater drain flow rate, a correct balance of the inflow / outflow flow rate can be obtained.
Therefore, the water level of the water tank of the deaerator can be controlled stably in any operating state of the plant.

In claim 9, the condensate recirculation flow rate and the low-pressure heater drain flow rate added in claim 8 can be obtained by the same method as in claim 2. Even if this is the case, stable control of the water level of the deaerator storage tank is possible.

In claims 10, 11, 12 and 13, since the respective numerical values required in claim 9 can be obtained, a correct or approximate flow value can be obtained.
Stable water level control of the deaerator storage tank is enabled.

In the fourteenth aspect, it is possible to obtain the required flow rate value by actually measuring the flow rate value additionally required in the eighth aspect, and it is possible to stably control the water level of the deaerator storage tank in any operation state of the plant. It becomes possible.

According to the fifteenth aspect, after switching from the auxiliary steam supply control to the bleeding supply from the steam turbine, the set value of the deaerator pressure controller, which is a predetermined pressure value, is increased. By following and changing the pressure at a value slightly lower than the internal pressure or the bleed pressure with the fall, the control can be smoothly switched to the auxiliary steam supply control.

In the sixteenth aspect of the present invention, the load suddenly drops such that a flush of the stored water occurs due to a delay in following the decrease in the stored water temperature of the water storage tank due to a decrease in the pressure in the deaerator, and F
When the pressure inside the chamber, the sleeve pressure, or the load drop rate exceeds a predetermined value at the time of CB and load interruption, the set value of the pressure controller is switched to a value slightly higher than the current chamber pressure or the extraction pressure. Set and start auxiliary steam supply control immediately. Thereafter, by lowering the set value at a rate of drop taking into account the followability of the stored water temperature drop and reaching a predetermined internal pressure value, the occurrence of flushing of the stored water in the storage tank can be suppressed or prevented. Operation and water level control of the water storage tank can be continued.

In the seventeenth aspect, the set value of the pressure controller when the load of the steam turbine drops is calculated and compared with the saturation temperature of the deaerator pressure and the water storage temperature of the water storage tank. The pressure value at which the temperature becomes higher than the water storage temperature is set as the pressure controller set value, and thereafter the set value is lowered at a predetermined descent speed to reach the predetermined internal pressure set value, thereby suppressing or preventing the flush of the water storage. BF is stable
The operation of P and the water level control of the water storage tank can be performed.

In the eighteenth aspect, the set value of the pressure controller at the time of the load drop of the steam turbine is calculated from the saturation temperature and the water storage temperature obtained from the pressure obtained by subtracting the water head from the suction pressure of the BFP to the water level of the water storage tank. It is possible to suppress or prevent flushing of the stored water by calculating the pressure value at which the stored water does not flush, or by comparing the saturation temperature obtained from the internal pressure with the BFP suction temperature, so that stable BFP operation and water level control of the water storage tank can be achieved. It becomes possible.

According to the nineteenth aspect of the present invention, when the storage water is flushed due to a sudden load drop of the steam turbine or the like, water having a temperature lower than the storage water temperature is injected into the water storage tank or the deaerator. Since the stored water temperature can be lowered at an early stage by discharging the matched water, and the flushing of the stored water due to the decrease in the internal pressure can be prevented, the stable operation of the BFP and the water level control of the water storage tank can be continued. The low-temperature water to be injected in claim 19 is intended to be the intended purpose by using a condensate booster pump or a condensate withdrawn from an outlet line of a condensate pump which is a stable supply source in any operation state of the plant. Since the temperature of the water in the water storage tank is lowered early by using water at a lower temperature, the flush of the water storage can be prevented, so that stable BFP operation and water storage can be achieved. The water level of the tank can be controlled.

According to the twenty-first aspect, the low-temperature water to be injected can be prevented from being flushed by using a low-pressure heater drain or by using the condensate in the twentieth aspect. Water level control becomes possible.

In claim 22, when condensing water or injecting low-pressure heater drain into the water storage tank or the deaerator,
Since the source of the stored water to be discharged is a storage tank or downcomer and the destination of the discharge is a condenser, water can be removed efficiently in the system and water can be efficiently replaced. In addition, stable operation of the BFP and control of the water level of the water storage tank can be performed.

In the twenty-third aspect, the flow rate control can be stabilized by additionally providing a spillover control valve as the operating end on the outflow side of the stored water, so that a stable operation of the BFP can be achieved.

According to the twenty-fourth aspect, the amount of low-temperature water injected into the water storage tank or the deaerator is a predetermined flow rate value in consideration of the replacement time of the storage water, that is, the storage flush due to the delay in following the reduction of the storage temperature due to a drop in the internal pressure. Injection flow rate control using a flow rate value to prevent the occurrence of the above problem, and by following a flow rate control valve or a motor-operated valve as the control operation end, water can be replaced at an early stage, and a stable BFP operation can be performed. Also, at this time, the outflow of the stored water is controlled to follow a value slightly larger than the injection flow rate, thereby avoiding an abnormal rise in the water level in the water storage tank, and replenishing the flow rate for the insignificant drop in the water level. By relying on the water tank water level system of the deaerator according to the first or eighth aspect, mutual interference can be avoided and the water tank control of the deaerator can be stably controlled.

In the twenty-fifth aspect, the injection amount of the low-temperature water into the water storage tank or the deaerator is set to follow-up control at a value slightly smaller than the outflow flow rate. By performing the outflow flow rate control using the value as a predetermined set value, stable operation of the BFP and control of the water level of the water tank of the deaerator become possible.

In the twenty-sixth aspect, the flow rate value required for the feedback flow rate control in the twenty-fourth and twenty-fifth aspects is determined by using an actual value measured by a flow rate detector and a flow rate transmitter attached to each pipe. ,
The flow rate can be controlled by using the values determined by the methods in 3, 4, and 6.

According to the twenty-seventh aspect of the present invention, when the operation of the plant is stabilized based on the measured value of the dissolved oxygen meter of the water stored in the water storage tank due to the high condensate of the dissolved oxygen or the injection of the heater drain, the deaerator circulation pump is operated. By combining with the condensate at the inlet of the deaerator and circulating it, it is possible to deaerate early, so that adverse effects on the piping and heat exchangers after the water storage tank including the poiler are minimized. Thus, stable operation of the plant can be continued.

[Brief description of the drawings]

FIG. 1 is a system diagram of a steam turbine plant including a deaerator control device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram when a differential pressure of a control valve is obtained by a differential pressure transmitter according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram in a case where a differential pressure of a control valve is obtained by two pressure transmitters according to the first embodiment of the present invention.

FIG. 4 is a system diagram of a steam turbine plant including a deaerator control device according to a second embodiment of the present invention.

FIG. 5 is a characteristic diagram showing pressure control characteristics of a deaerator in a deaerator control device according to a third embodiment of the present invention.

FIG. 6 is a characteristic diagram showing pressure control characteristics of the deaerator in the deaerator control device when the steam turbine extraction pressure or the steam turbine load is sharply reduced in the third embodiment of the present invention.

FIG. 7 is an explanatory diagram of an example of a process amount detection point in a case where the deaerator control device according to the third embodiment of the present invention controls the deaerator water temperature to be equal to or lower than a saturation temperature at which no flash occurs. .

FIG. 8 shows another example of the process amount detection point when the deaerator control device according to the third embodiment of the present invention controls the deaerator water storage temperature to be equal to or lower than a saturation temperature at which no flash occurs. FIG.

FIG. 9 illustrates another process amount detection point in the case where the deaerator control device according to the third embodiment of the present invention controls the deaerator storage water temperature to be equal to or lower than a saturation temperature at which no flash occurs. FIG.

FIG. 10 is a system diagram of a steam turbine plant including a deaerator control device according to a fourth embodiment of the present invention.

FIG. 11 is a system diagram of a steam turbine plant including a deaerator control device according to a fifth embodiment of the present invention.

FIG. 12 is a system diagram of a steam turbine plant including a deaerator control device according to a sixth embodiment of the present invention.

FIG. 13 is a system diagram of a steam turbine plant including a deaerator control device according to a seventh embodiment of the present invention.

FIG. 14 is a system diagram of a steam turbine plant including a conventional deaerator control device.

[Explanation of symbols]

 76 Deaerator water level controller 77 Deaerator water level control valve 81 Deaerator pressure transmitter 82 Deaerator pressure controller 83 Deaerator pressure control valve small valve 84 Deaerator pressure control valve large valve 91 Deaerator Heated steam flow detector 92 Deaerator heated steam flow transmitter 93 High pressure feed water heater drain flow detector 94 High pressure feed water heater drain flow transmitter 95 Low pressure cleanup circulation flow detector 96 Low pressure cleanup circulation flow transmitter 97 Water recirculation flow detector 98 Condensate recirculation flow transmitter 99 Low pressure heater drain flow detector 100 Low pressure heater drain flow transmitter 111a, b, c Temperature reduction pipe 112 Flow control valve or electric valve 113 Spillover pipe 114 Spillover control valve 121 Desorption Vapor circulation pipe 122 Deaerator circulation pump 123 Check valve

Continued on the front page (72) Inventor Hiroshi Murata 2-4 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Keihin Works, Toshiba Corporation (72) Inventor Masaaki Tanabe 66-2, Horikawacho, Sai-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba Engineer Inside the Ring Co., Ltd. (72) Inventor Haruhiko Uno 66-2, Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside (72) Inventor Takahiro Komine 66-2, Horikawa-cho, Sai-ku, Kawasaki-shi, Kanagawa Toshiba Engineer Ring Co., Ltd.

Claims (27)

[Claims] The present invention detects a change in a water level of a water storage tank of a deaerator, a flow rate of a condensed water flowing into the deaerator and a flow rate of an outgoing feedwater from the deaerator, and adjusts the flow rate of the condensed water. In the deaerator control device for controlling the water level of the water storage tank by a three-element water level control for keeping the water level of the water storage tank constant, the inflow condensate flow rate is equal to the deaerator inlet condensate flow rate and the deaerator heating steam flow rate and the high pressure. A deaerator control device characterized by using a flow rate obtained by adding a feed water heater drain flow rate, and using a flow rate obtained by adding a low pressure clean-up circulation flow rate to a boiler inlet feed water flow rate as the outflow feed water flow rate. 2. The deaerator heating steam flow rate, high pressure feed water heater drain flow rate, and low pressure cleanup circulation flow rate are as follows: Q is the flow rate passing through each control valve, Cv is the capacity coefficient of the control valve,
When the pressure difference before and after the control valve is ΔP and the specific gravity of the fluid is G,
The deaerator control apparatus according to claim 1, wherein a flow rate determined by Q = (Cv / 1.17)） (ΔP / G) is used. 3. The differential pressure before and after the control valve is a detection signal of a differential pressure transmitter for detecting the differential pressure before and after the control valve, or a differential signal from two pressure transmitters provided before and after the control valve. The deaerator control device according to claim 2, wherein a difference between the detection signals is used. 4. The deaerator control device according to claim 2, wherein the specific gravity of the fluid uses a specific gravity calculated based on a fluid temperature upstream of the control valve. 5. The specific gravity of the fluid uses a specific gravity calculated based on a fluid temperature based on a plant thermal equilibrium diagram for each load of the steam turbine, which is planned in advance, and the differential pressure across the control valve is a pipe pressure loss. 3. The deaerator control apparatus according to claim 2, wherein a pressure difference taking into account a difference in head between the upstream and downstream processes is used. 6. The decoupling device according to claim 2, wherein the capacity coefficient of the control valve uses a capacity coefficient obtained based on a detection signal of an opening transmitter of the control valve. A porcelain control device. 7. The deaerator heating steam flow rate, high pressure feed water heater drain flow rate, and low pressure cleanup circulating flow rate use values measured by a flow rate detector and a flow rate transmitter attached to each piping line. The deaerator control device according to claim 1. 8. The condensate recirculation flow is subtracted from the condensate booster pump outlet condensate flow instead of the deaerator inlet condensate flow, and the low pressure heater drain flow from the low pressure heater drain tank is added. The deaerator control apparatus according to claim 1, wherein the condensate flow rate is used. 9. The condensate recirculation flow rate and the low-pressure heater drain flow rate are as follows: the flow rate passing through each control valve is Q, the capacity coefficient of the control valve is Cv, the differential pressure before and after the control valve is ΔP, and the specific gravity of the fluid is When G, Q = (Cv / 1.17) · √ (ΔP
The deaerator control device according to claim 8, wherein the flow rate determined in / G) is used. 10. The differential pressure before and after the control valve is a detection signal of a differential pressure transmitter for detecting the differential pressure before and after the control valve, or a differential signal from two pressure transmitters respectively provided before and after the control valve. 10. The method according to claim 9, wherein a difference between the detection signals is used.
3. The deaerator control device according to 1. 11. The deaerator control device according to claim 9, wherein the specific gravity of the fluid uses a specific gravity calculated based on a fluid temperature upstream of the control valve. 12. The specific gravity of the fluid uses a specific gravity calculated in advance based on a fluid temperature according to a plant thermal equilibrium diagram for each load of the steam turbine, and a differential pressure between before and after the control valve is determined by a pipe pressure loss. The deaerator control device according to claim 9, wherein a pressure difference taking into account the head difference between the upstream and downstream processes is used. 13. The device according to claim 9, wherein the capacity coefficient of the control valve uses a capacity coefficient obtained based on a detection signal of an opening degree transmitter of the control valve. A porcelain control device. 14. A degassing apparatus according to claim 8, wherein the condensate recirculation flow rate and the low-pressure heater drain flow rate use values measured by a flow rate detector and a flow rate transmitter attached to each piping line. A porcelain control device. 15. A flow rate of the inflow condensate is adjusted by detecting a change in a water level of a water storage tank of the deaerator, a flow rate of condensate water flowing into the deaerator and a flow rate of feedwater flow out of the deaerator. In a deaerator control device for controlling the water level of the water storage tank by a three-element water level control for keeping the water level of the water storage tank constant, when the auxiliary steam is supplied to the deaerator, the pressure in the deaerator is predetermined. The set value of the deaerator pressure controller that adjusts the pressure control valve to become the set value of, after the bleeding supply from the steam turbine to the deaerator is started, the deaerator internal pressure or A deaerator control device characterized in that the follow-up change is performed at a value slightly lower than the extraction pressure from the steam turbine. 16. The set value of the deaerator pressure controller that changes with a value slightly lower than the deaerator internal pressure or the extraction pressure from the steam turbine is the deaerator internal pressure, 16. The deaerator control device according to claim 15, wherein when the extraction pressure from the steam turbine or the drop rate of the load exceeds a predetermined value, the pressure is changed at a predetermined drop rate. . 17. The set value of the deaerator pressure controller is such that a saturation temperature obtained based on the deaerator internal pressure is higher than a storage water temperature of the water storage tank or a suction water supply temperature of a boiler water supply pump. The deaerator control device according to claim 16, wherein the pressure value is set as follows. 18. The method according to claim 1, wherein the saturation temperature in the deaerator is obtained based on a pressure obtained by subtracting a water head to a water storage tank from a suction pressure of a boiler feed pump.
8. The deaerator control device according to 7. 19. The flow rate of the inflow condensate is adjusted by detecting a change in a water level of a water storage tank of the deaerator, an inflow condensate flow into the deaerator and an outflow water supply flow from the deaerator. In the deaerator control device for controlling the water level of the water storage tank by a three-element water level control that keeps the water level of the water storage tank constant, at the start of the first cutback operation, the water storage temperature in the water storage tank or the deaerator is lower than the water storage temperature. A deaerator control device characterized by injecting low-temperature water and draining water corresponding to the low-temperature water. 20. The deaeration according to claim 19, wherein the water injected into the water storage tank or the deaerator is condensate taken out from an outlet line of a condensate booster pump or a condensate pump. Control device. 21. The deaerator according to claim 19, wherein the water injected into the water storage tank or the deaerator is a low-pressure heater drain taken from a low-pressure heater drain pump outlet line. Control device. 22. The method according to claim 20, wherein the source of the storage water to be discharged when the condensate or the low-pressure heater drain is injected is the storage tank or the downcomer, and the discharge destination is a condenser. The deaerator control device according to claim 21. 23. The water discharged when the condensed water or the low-pressure heater drain is injected is discharged using both a spillover control valve provided in a spillover pipe and a low-pressure cleanup control valve provided in a low-pressure cleanup pipe. 23. The deaerator control device according to claim 22, wherein 24. An injection amount of water to be injected into the water storage tank or the deaerator is controlled by an injection flow rate based on a predetermined flow rate considering a replacement time of the storage water, and an outflow flow rate of the storage water is slightly larger than the injection flow rate. 22. The deaerator control device according to claim 20, wherein the flow rate is controlled by following. 25. The flow rate of the water to be injected into the water storage tank or the deaerator is controlled as a follow-up flow rate control at a value slightly smaller than the flow rate of the stored water. 23. The method according to claim 22, wherein
Or the deaerator control device according to claim 23. 26. The flow rate value fed back to the flow rate control of the flow rate of the water injected into the water storage tank or the deaerator and the flow rate of the stored water is determined by a flow rate detector and a flow rate transmitter attached to each piping line. 26. The deaerator control device according to claim 24, wherein the measured value according to the above is used, or the flow value obtained in claim 2 is used. 27. After reaching the single operation load in the power plant and continuing the stable operation by the first cut-back operation, the first cut-back operation is performed according to the dissolved oxygen value of the stored water or the relationship between the stored water temperature and the saturation temperature of the internal pressure of the device. 20. The deaerator control device according to claim 19, wherein the air circulation pump is started, operated, and stopped.